TY - JOUR
T1 - Characterization of nano-quasicrystal-formation in correlation to the local structure in Zr-based metallic glasses containing Pd
AU - Saida, Junji
AU - Yamada, Rui
AU - Kozikowski, Paweł
AU - Imafuku, Muneyuki
AU - Sato, Shigeo
AU - Ohnuma, Masato
PY - 2017/6/15
Y1 - 2017/6/15
N2 - The effect of a noble metal (Pd) on the local atomic structure of the glassy state and the transformation behavior of quasicrystal (QC) precipitation in Zr70(Cu and Ni)30-xPdx (x = 0, 5, 10, 20) alloys were investigated. A QC phase precipitates in Zr-Cu glassy alloys at Pd concentrations of 5–20 at.% and in Zr-Ni glassy alloys at Pd concentrations of 10–20 at.%. The radial distribution function (RDF) indicates a change in the local atomic structure upon the addition of Pd. The QC phase is abruptly formed from the glassy structure above a certain temperature. The activation energy for nucleation is much larger than that for the precipitation of conventional intermetallic compounds. The QC growth is suddenly suppressed when their diameter reaches approximately 20 nm. The cooperative motion of icosahedral clusters as the precipitation mechanism was discussed. It was assumed that QC nucleus has a Zr-centered icosahedral medium-range order (MRO) as its core, and it grows by the aggregation of surrounding small icosahedral clusters. Noble metals might play a role of stabilizing the individual Zr-centered icosahedral MROs.
AB - The effect of a noble metal (Pd) on the local atomic structure of the glassy state and the transformation behavior of quasicrystal (QC) precipitation in Zr70(Cu and Ni)30-xPdx (x = 0, 5, 10, 20) alloys were investigated. A QC phase precipitates in Zr-Cu glassy alloys at Pd concentrations of 5–20 at.% and in Zr-Ni glassy alloys at Pd concentrations of 10–20 at.%. The radial distribution function (RDF) indicates a change in the local atomic structure upon the addition of Pd. The QC phase is abruptly formed from the glassy structure above a certain temperature. The activation energy for nucleation is much larger than that for the precipitation of conventional intermetallic compounds. The QC growth is suddenly suppressed when their diameter reaches approximately 20 nm. The cooperative motion of icosahedral clusters as the precipitation mechanism was discussed. It was assumed that QC nucleus has a Zr-centered icosahedral medium-range order (MRO) as its core, and it grows by the aggregation of surrounding small icosahedral clusters. Noble metals might play a role of stabilizing the individual Zr-centered icosahedral MROs.
KW - Local structure
KW - Metallic glasses
KW - Nucleation
KW - Quasicrystallization
KW - Zirconium-based alloy
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U2 - 10.1016/j.jallcom.2016.10.270
DO - 10.1016/j.jallcom.2016.10.270
M3 - Article
AN - SCOPUS:85006155754
VL - 707
SP - 46
EP - 50
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
SN - 0925-8388
ER -